1. Field of the Invention
The present invention relates to a modular assembly for support and powered lateral translation of forks in lift trucks.
2. State of the Prior Art
About 75% of lift trucks are equipped with lateral translation devices for the forks that are generally formed of two slidably coupled frames, one designed for hooking on the truck and the other for support of the forks. Also provided between the frames is a hydraulic or electric powering system for relative side translation of one frame with respect to the other.
These devices are substantially divided into two big categories: translators designed to be hooked to the normal fork-carrying plate of the truck and integral translators, mounted in place of the fork-carrying plate.
In the first case there is the advantage of utilizing the fork-carrying plate with which all trucks are provided since the origin. On the other hand, there is the disadvantage that mounting on the fork-carrying plate involves forward displacement of the nominal center of gravity of the load of about 5.5% (relative to the front wheel axis of the truck), due to the thickness of the pair of frames, which will bring about a reduction of same amount in the rated capacity load of the truck.
The integral translators mounted in place of the fork-carrying plate eliminate the thickness of the plate itself (that generally can be compared to the thickness of one of the two frames). In this manner forward displacement of the center of gravity of the load is reduced to about 2.5%, therefore with a higher residual capacity load of the lift truck as compared with the hooked model.
Since the integral translator represents an improvement relative to the hooked translator, it encounters greater favor on the market.
Application of the integral translator however involves some disadvantages for truck manufacturers, among which there is first of all a severer programming of the truck production, since the trucks on which the integral translator is to be mounted must be defined in advance because they need to be devoid of the fork-carrying plate. Experience has proved that often with lift truck retailers the truck version required by the customer very often is not ready on the market, so that very expensive dismantling and replacement operations are necessary.
This fact is much more frequent when the truck manufacturer is in another country or continent, the truck models are more standardized and the amounts of trucks present with the retailer are higher.
The problem is made worse by the fact that generally different versions are provided for each integral translator (in order to optimize performance, based on the type of truck, the work environment and use), said translators differentiating from each other for the type of slide guides (guides provided with runners, rollers or mixed guides) and for the type of power supply (hydraulic or electric power supply). Generally there is a version provided with upper and lower runners (made of a high-strength special resin with self-lubricating additives) and with a hydraulic jack, of a more reduced cost and adapted for indoor uses and clean outdoor environments; a version provided with upper runners and lower rollers also having a hydraulic jack, recommended for damp, acid and dusty environments where the lower runners would need a more frequent servicing; and a version provided with upper and lower rollers and with an electric actuator, designed for electric trucks, because it enables a very important energy saving.
It is a general aim of the present invention to obviate the above mentioned drawbacks by providing a modular assembly enabling a selection among the different possibilities so that a truck will be provided with the desired translation system in an easy and inexpensive manner and with a minimum loss of capacity load.